Keep the question small
An experiment becomes manageable when it starts with one question: can this page be clearer, can this interaction feel simpler, can this layout adapt to its content?
Finish a small version
A working version reveals things a sketch cannot. Put the real copy in. Try a long name. Use the page with one hand. The answers tend to be more useful than another hour of polishing an isolated component.
Keep a record
Write down the decision and what led to it. A short note gives the next experiment a better starting point. Over time, those notes become a record of how your thinking has changed.